EFFECTS OF EXCESS OXYGEN ON THE PROPERTIES OF REACTIVELY SPUTTERED RUOX THIN-FILMS

Conducting RuOx thin films are fabricated by reactive sputtering with Ar+O2 plasma for an application as the bottom electrode in a ferroelectric thin film capacitor. The structure and composition of RuO x should be controlled to promote the required characteristics in the deposited ferroelectric film. The stoichiometry and resistivity of RuO x are easily controlled by varying the relative O2 partial pressure in the sputtering ambient between 10% and 50%, where the oxygen composition is varied from 2.0 to 2.4 and the resistivity of 100-nm-thick RuO2 film is changed from 145 to 280 μΩ cm corresponding to the variation of oxygen concentration. The films deposited in O2 pressures lower than 30% show preferential (110) RuO2 grain growth, whereas they show (101) in higher O2 pressures. The films deposited at high O2 pressures show some decomposition of the film during a high temperature annealing in N2 ambient. © 1995 American Institute of Physics.